The present invention relates generally to servo positioned actuators, and more particularly, to a carriage and positioning actuator assembly in which at least part of the carriage is positioned within the central portion of the motor.
Information is recorded on and read from a moving magnetic tape with a magnetic read/write head positioned next to the tape. The magnetic xe2x80x9cheadxe2x80x9d may be a single head or, as is common, a series of read/write head elements stacked individually and/or in pairs within the head unit. Data is recorded in tracks on the tape by moving the tape lengthwise past the head. The head elements are selectively activated by electric currents representing the information to be recorded on the tape. The information is read from the tape by moving the tape longitudinally past the head elements so that magnetic flux patterns on the tape create electric signals in the head elements. These signals represent the information stored on the tape.
Data is recorded on and read from each of the parallel tracks on the tape by positioning the head elements at different locations across the tape. That is, head elements are moved from track to track as necessary to either record or read the desired information. Movement of the magnetic head is controlled by an actuator operatively coupled to some type of servo control circuitry. Tape drive head positioning actuators often include a lead screw driven by a stepper motor, a voice coil motor, or a combination of both. The carriage that supports the head is driven by the actuator along a path perpendicular to the direction that the tape travels. The head elements are positioned as close to the center of a track as possible based upon the servo information recorded on the tape.
The present invention is directed in general to a servo positioned carriage and actuator assembly and, more particularly, to a head carriage and actuator assembly for a tape drive. A part of the carriage is positioned within the central portion of the motor. The motor, typically a voice coil motor, includes a coil of electrically conductive windings and a magnet or magnets adjacent to the coil. In one embodiment of the invention, the central portion of the motor is defined by a perimeter of the magnets and the carriage is positioned at least partially inside this perimeter. The carriage, for example, will typically include a ring shaped center portion in which the coil is mounted. This ring shaped center portion mounting the coil is positioned inside the magnets to help minimize the overall mass of the carriage elements of the assembly.